Fluids are transported for the most varied purposes by means of pumps or similar fluid delivery means in channel, sewer or duct systems. A plurality of such fluid conducting systems with fluid delivery means serve to bring a fluid for a specific action into a space or a room, or remove it therefrom, the fluid being conveyed between the space and the duct by openings in the surface bounding the space or through an open duct end.
Examples of such fluid conducting systems are systems for evacuating spaces, systems for gassing or gas infection of spaces, systems for heating or cooling spaces by transporting fluid heat carriers through the spaces or systems for removing solids or other fluids from spaces by utilizing the kinetic energy of the fluids supplied to the spaces. In many of these applications it would be desirable for the most varied reasons to be able to transport the fluid as a continuum through the surface bounding the space, in such a way that all points of said surface would be identical with respect to the fluid passage. In the prior art this wish is approximately fulfilled by providing a large number of duct ends opening into the space providing larger duct ends closed with a porous wall and between the duct ends and porous wall a distributing space is provided. The finer the pores of such porous walls, the higher the pressure gradient necessary in order to deliver the fluid through the wall, which in turn increases the demands concerning the mechanical stability of the wall. Therefore, for each application a procedurally economic optimum must be sought between a surface continuity of the fluid delivery over the complete surface through which the flow is to take place still satisfying the requirement and a still acceptable level of the necessary pressure difference.